I get this question a lot and the only answer I can think of is it depends. There are a lot factors that determine how much food the worms will eat, the type of food, how big the pieces are, the temperature and moisture in the bin. So rather than give an amount of food that could lead to missed expectations and disappointment, I’ll give a few options to find out for yourself.
The first option is to add food, a little at a time, checking how long it takes to compost. I’d start with about the same weight as the worms. The smaller the pieces, the faster it breaks down and different foods compost at different rates so some items may compost faster than others. This is the option most sites recommend to minimize potential problems like smells or fruit flies. Check on the bin every 2-3 days and mix regularly.
Personally, however, I think you want to feed your worms whatever you got rather than measure an amount of food for your worms so I’d try adding your usual food waste and check the bin regularly, every 2-3 days. You can store the food for 2-3 days and add and check at the same time. If when you check on the bin the food hasn’t decomposed then hold off on adding more food until that food is composted. Check to make sure there is no mold or strong smells and give it a good mix to help the process along. Make sure the food is well covered with compost and brown paper before closing it up. If you see mold or if strong smells develop, remove the moldy or smelly food but ideally you’d want to avoid this by regular checks and mixing. I’d only recommend this method if you’re checking your bin regularly. Otherwise mold, pests, and smells could develop before you get a chance to adjust.
I like this method because I think worms adapt to their bin. By adding more food, the hope is that they rise to the challenge by producing more worms or eating more food. I haven’t found many online references about this other than a general reference that worms regulate their population based on the availability of food and space so there’s no worry of overcrowding. But I also know every year at thanksgiving when I have triple the amount of food waste the worms always seem to be fine and after watching my bin over the years, I’ve found that worms are generally pretty adaptable. If you’re checking regularly you can always adjust as needed.